摘要
针对上软下硬复合地层盾构隧道施工阶段千斤顶推力不均造成管片裂损问题,基于扩展有限元理论,运用ABAQUS有限元软件,建立管片三维有限元模型,模拟3种推力不均工况,对裂纹形态特征、扩展规律、扩展路径进行分析,并提出相应的工程改进措施。研究结果表明:管片裂纹多位于最大推力位置,裂纹形态表现为边角部、手孔和螺栓孔附近大范围线状裂纹。千斤顶推力大小、位置与管片裂纹的分布形态直接相关,千斤顶推力越大,最大推力位置越靠近端部,管片裂损区域越大。裂纹扩展呈现台阶式递增的特点,可以分为3个阶段,第三阶段的裂纹扩展最迅速,管片结构出现区域性破坏。通过优化管片结构、控制施工不良荷载与盾构姿态等措施,可减轻盾构施工阶段管片裂损程度。
The non-uniform jacking loads can cause cracks of the segment at the stage of the tunnelconstruction in the upper-soft and lower-hard ground. Based on the extended finite element method, arefined 3D model of the segment is established by using ABAQUS finite element software. Threeconditions of the non-uniform jacking loads on the segment are simulated and crack shape, propagationlaw and propagation path are analyzed. Meanwhile, corresponding engineering improvement measures areput forward. The results show that cracks of the segment are mostly located in the positions of themaximum jacking loads. The cracks in the segment are large linear cracks near the corner, hand hole andbolt hole. The load and position of jacks are directly related to the distribution of cracks. The larger thejacking load, the closer the maximum jacking load to the end, and the larger the region of the segmentcracking. The propagation of cracking length tends to increase by steps, which can be divided into threestages. In the third stage, the crack propagation is most rapid and the segment structure is subjected toregional failure. By optimizing the structure of the segment, controlling the load of the construction andthe attitude of the shield, the degree of crack damage at the stage of the tunnel construction can bereduced.
作者
苏昂
SU Ang(Key Laboratory of Transportation Tunnel Engineering,Ministry of Education,Southwest Jiaotong University,Chengdu 610031,China)
出处
《铁道标准设计》
北大核心
2018年第11期103-107,113,共6页
Railway Standard Design
基金
国家自然科学基金(51278424
51578461)
关键词
上软下硬地层
盾构隧道
管片
数值计算
千斤顶推力不均
裂纹扩展
Upper-soft and lower-hard ground
Shield tunnel
Segment
Numerical calculation
Non-uniform jacking loads
Crack propagation
